NAA10-related syndrome is an extremely rare X-chromosomal disorder, the symptoms of which include intellectual disability (ID), ocular anomalies, or congenital heart diseases, such as hypertrophic cardiomyopathy (HCM). Here, we describe a 4-year-old Japanese male patient who exhibited mild ID, HCM, and specific facial features. A hemizygous mutation (NM_003491.3: c.455_458del, p. Thr152Argfs*6) in exon 7 of NAA10 was detected. We recommend that patients undergo precise medical follow-up considering the characteristics of NAA10-related syndrome.

CLOVES syndrome is characterized by congenital lipomatous overgrowth, vascular malformation, epidermal nevi, and scoliosis/spinal malformation. It is caused by somatic mosaicism of gain-of-function variants of PIK3CA . Here, we describe a novel case of a 5-year-old Japanese girl with CLOVES and concurrent pancreatic steatosis. She had a recurrent somatic mutation in PIK3CA (NM_006218.3: c.1357G>A, p.Glu453Lys), elevated HbA1c levels, and pancreatic steatosis. This case indicates that pancreatic screening is critical for PIK3CA- related disorders.

The 20q11.2 microdeletion is a rare chromosomal aberration characterized by intellectual disability (ID), motor developmental delay, neonatal feeding problems, and facial dysmorphism. Here, a 2-year- and 6-month-old Japanese girl with a 1.2 Mb microdeletion of 20q11.2 showed ID, motor developmental delay, and distinctive facial features without feeding problems. The deleted region was identified by array-based comparative genomic hybridization and is the smallest reported for a 20q11.2 microdeletion.

Transient receptor potential channel C6 encoded by TRPC6 is involved in slit diaphragm formation in podocytes, and abnormalities of the TRPC6 protein cause various glomerular diseases. The first identified pathogenic variant of TRPC6 was found to cause steroid‐resistant nephrotic syndrome that typically developed in adulthood and then slowly led to end‐stage renal disease, along with a renal pathology of focal segmental glomerulosclerosis. Here, we report a patient with rapidly progressing infantile nephrotic syndrome and a heterozygous missense TRPC6 variant. The patient, a 2‐year‐old Japanese boy, developed steroid‐resistant nephrotic syndrome at age 11 months. His renal function deteriorated rapidly, and peritoneal dialysis was introduced at age 1 year and 6 months. His renal pathology, obtained at age 1 year and 1 month, was consistent with diffuse mesangial sclerosis (DMS). Clinical exome analysis and custom panel analysis for hereditary renal diseases revealed a reported heterozygous missense variant in TRPC6 (NM_004621.5:c.523C > T:p.Arg175Trp). This is the first report of a patient with a TRPC6‐related renal disorder associated with DMS.